Sanju Samson and Tilak Varma made unbeaten centuries to lead India to a 135-run win over South Africa in Johannesburg and a 3-1 win in the T20 series.
Samson hit 109 off 56 balls and Varma hit 120 off 47 in a stunning unbroken stand of 210 for the second wicket as India scored 283-1.
It is the first time that two teammates have scored centuries in the same innings of a men's T20 international between full member nations.
In return, South Africa were bowled out for 148 from 18.2 overs with Arshdeep Singh taking 3-20.
The left-handed Varma smashed nine fours and 10 sixes to join Samson on 73-1 in the sixth over after Abhishek Sharma was dismissed for 36 off 18.
With an unbeaten score of 107 in the third T20, Varma becomes the second Indian and fifth batsman overall to hit centuries in consecutive men's T20 internationals.
Wicketkeeper Samson became the first Indian to achieve this feat He hit 107 in the first T20 of this series.
In the fourth and final T20 at the Wanderers Stadium, Samson hit six fours and nine sixes.
His partnership of 210 with Varma is the sixth highest in any men's T20 international, the highest for the second wicket and the highest for India.
India's 283-1 is their second highest tally in men's T20 internationals after their 297-6 against Bangladesh in October.
Varma reached his target in just 41 balls, making him the third-fastest century by an Indian batsman in men's T20 internationals after Rohit Sharma (35 balls against Sri Lanka in 2017) and Samson (40 balls against Bangladesh in October).
South Africa slumped to 10-4 in return before Tristan Stubbs scored 43 from 29, but the Proteas still suffered their heaviest T20 international defeat by runs.
